According to the Ramayana trail Sri Lanka , both Lord Rama and Lakshman were seriously injured and wounded by powerful arrows and fell unconscious during the war with Ravana’s army. So Lord Hanuman was instructed by Sugriva to fetch lifesaving herbs which only grew in Himalayas. It is stated that as he was unable to identify that lifesaving herb himself alone, Hanuman carried out the whole Himalayan mountain range to Sri Lanka. Then it is believed that parts from Himalayas fell on five places in Sri Lanka and those five places declared as “Sanjeevani drops”
List of Sanjivani (Sanjeevini) mountains in Sri Lanka